Method of crimping a socket to a rod formed of aluminum material

ABSTRACT

Method and apparatus for crimping a socket to a rod formed aluminium material using a matrix and a mandrel. The force acting upon the mandrel shall exceed the formula G A/52 + 1.6 and be below the formula G A/38 + 3.0, G is stated in tons and A in mm2. The formulas are usable within the area 25 - 500 mm2 for the rod formed material.

United States Patent [191 Svensson [11] 3,828,420 Aug. 13, 1974 METHOD OF CRIMPING' A TO A ROD FORMED OF ALUMINUM MATERIAL [76] Inventor: Uno Svensson, Porlabacken 5,

Bandhagen, Sweden [22] Filed: Oct. 7, 1971 [21] Appl. No.: 187,565

[30] Foreign Applieation Priority/Data Oct. 9, 1970 Sweden 13678/70 [52] U.S. Cl. 29/517, 29/200 B, 29/203 D, 140/113 [51] Int. Cl B21d 39/00, 823p 11/00 [58] Field of Search 29/517, 203 D, 200 B; 7 140/113 [56] I References Cited UNITED STATES PATENTS Davis 29/517 2,467,012 4/1949 Deuschle..

2,763,171 9/1956 Modrey et al 29/517 UX FOREIGN PATENTS OR APPLICATIONS 778,367 7/1957 Great Britain 29/517 544,565 9/1922 France 29/517 27,885 9/1924 France .Q 29/517 Primary ExaminerCharlie T. Moon [57 ABSTRACT- Method and apparatus for crimpinga socket to a rod formed aluminium material using a matrix and a mandrel. The force acting upon the mandrel shall exceed the formula G =A/52 1.6 and be below the formula G =A/38 3.0, G is stated in tons and A in mm. The formulas are usable within the area 25 500 mm for the rod formed material.

5 Claims, 8 Drawing Figures PAIENIEDAum 31m,

SHEEI 1 [IF 3 PAIENIEB we 1 31974 SHEEIF3 A 3 C 1) E METHOD OF CRIMPING A SOCKET TO A ROD FORMED OF ALUMINUM MATERIAL BACKGROUND OF THE INVENTION Field of the Invention The present invention refers partly to a method for crimping a socket to a rod formed aluminium material, especially in the form of a cable with the aid of indentation partly to an apparatus for executing the method. The method according to the present invention and the apparatus is using a number of indentations. A socket shall be placed over one or both ends of the aluminium material and these shall be placed in a matrix, which prevents flow of the socket material, the indentations will be formed by the aid of one or more mandrels and that at last the matrix will be taken away.

By crimping connecting sockets to rod formed aluminium material, as an example electrical wires, it has been noted that the socket as well as the rod formed material will show an extension caused by the crimping force. This extension is depending upon a plurality of factors but the crimping surface in the apparatus has a primary effect. The used material is also essential and if the material is aluminium especially troublesome conditions will occur.

It has been troublesome to form the crimping sur faces in the apparatus so that the extension is eliminated. The reason might be that a certain deformation and a high pressure to the socket and the material is necessary in order to achieve an acceptable connection, preferably a molecular connection, between the parts. In case a mandrel is used, which is pressed into the socket and the material, not only an extension is noted but also a radial directed flow of the material.

Summary of the Invention The present invention is based upon practical tests. Because of the disadvantageous stated above it is a desire to cause so small indentations as possible in order to eliminate the extension tendency. A small indentation does not give any confidence that the two parts have been connected to each other satisfactory. According to the present invention the area reduction shall be with in the area percent and at the same time the pressure on each mandrel shall be within the area of 2.5 15 tons.

The most significant features of the present invention is stated in the characterizing parts of the succeeding claims.

The used method according to the invention is intended to crimp a socket to a rod formed soft material and the socket is intended to surround the rod formed material, preferably aluminium material. The socket as well as the rod formed material should be of the same material. When the socket and the rod formed material, in the form of a wire, have been placed together, these are moved to an apparatus together with a matrix. Said matrix has two surfaces intended to prevent that the wire and the socket or only the socket is given an extension or thicken by the crimping, when the mandrel is moved into the socket and the wire. After the parts have been placed in the matrix the mandrel .is moved into the socket and also into the wire and during this crimping it is not possible for the socket nor for the wire, to get an extension nor a thicken, when these changings should exceed the distance between the inner surfaces, because these forms a stop for the flow of the material. After the crimping the matrix is taken away from the socket. In order to be sure that the socket and the wire have a sufficient good connection to each other without the need of cutting the connec- .tion area for ocular inspection, the indentations have a plane and smooth form. Moreover it is essential that the indentations shall cause an area reduction, compared to the original areas of the socket and the wire, within the range 10 25 percent, independent of the total area. The pressure on the mandrel shall be within the range 2.5 15 tons, the lower value is used for smaller area, as 25 mm and the higher value is used for larger area, as 500 mm. The invention is especially useful when the material of the socket and the wire are so choosen that the area reduction is essentially the same in the two parts, whereby is secured for a good contact and connection between the parts. The area reduction may also be within the range 10 20 percent and also within the range 12 18 percent has acceptable results been noted in spite of the large area range within which the invention is usable.

BRIEF DESCRIPTION OF THE DRAWINGS One among many apparatus which can be used for the described method shall be described with reference to the attached drawing in which FIG. 1 shows a perspective view of a crimping apparatus,

FIGS. 2a and 2b show different projections of a matrix,

FIG. 3 shows a perspective view of a socket and a electric wire placed in a matrix.

FIG. 4 shows a table over results from practical tests.

FIG. 5 shows a diagram in which the pressure force is stated compared to the area and FIGS. 6 and 7 show different projections of a mandrel.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 shows a crimping apparatus in which 1 designates a hydraulic pump, which is driven by a reciprocal movement of an arm 2. Said arm 2 may have a pressure plate 3 cooperatable with a foot. Said pump 1 has a hose 4 for the pressure media connected to a crimping head 5. Said head 5 has a cylinder (not shown) which is connected to said hose 4. In the cylinder is a piston which is acting upon a mandrel 6. Two parallel arms 7 are passing the mandrel 6 and the outer ends of which are bent to form a hook 8, cooperatable with recesses in a die 9, which die is intended to be placed between the arms 7. The die 9 is serving as a dolly or holder-on for the pressure from the mandrel and has a recess 10 formed to cooperate with the matrix or the socket for the wire depending upon the intended use of the apparatus.

The apparatus may be used in crimping without matrix, which might be recommended when crimping material as copper. The present invention is intended to deal with softer material as aluminium and by use of a matrix, whereby is eliminating the risk of increasing the length or the thickness of the connection when crimping.

FIGS. 2a and 2b show the matrix, which is devided into two parts, and has been given the reference number 11. The interior surface 12 is cylinder formed. The

surface 12 is at its ends formed with a perpendicular to said surface 12 directed surface 12 intended to face a surface on the socket. The surface 12 surrounds a circular hole 14, the diameter of which is smaller that that of the matrix of the surface 12, in order to get a better correspondency to the socket. The surface 12 serves as a limitting surface for the thicken of the socket when crimping, using the mandrel 6, and the surface 12' serves as limitting surface for the extension of th socket when crimping.

The matrix is formed with a longitudinal recess intended to permit free passage of the mandrel 6 through the matrix 11 and into the socket surrounded the electrical wire.

Moreover the matrix is hinged at its long side by a link 16 in which the rotation axis is parallel to the central line of the matrix.

In the preferred embodiment the socket consists of a joint socket in the form of a hollow cylinder socket 17. The socket 17 has an uniform thickness exept of a recess 18 caused by the length of the socket 17. The distance between the outer end of the socket l7 and the recess 18 is smaller than that of the distance between the surfaces 12' in the matrix 11. The recess 18 and the outer end forms the surface 13. The electrical aluminium wire 19 is placed inside the socket 17 and by connecting two electrical wires the wire 19 is moved into the socket l7 half its length and the wire 19 and the socket 17 are crimped together after the matrix 11 has been placed so it surrounds the socket 17, when the mandrel 6 is forced into the socket and the wire. In the right part of the socket 17 in FIG. 3 this has been illustrated by indicating the indentations and 20". By the force a molecular connection between the aluminium socket and the aluminium wire 19 is achieved. Neither a radial nor a axial extension may occur thanks to the surfaces 12 and 12.

In FIG. 3 is shown how the socket 17 is placed into the matrix 11 and how the surface 13 of the socket 17 is facing the surface 12 of the matrix in the purpose of preventing an extension of the socket 17 by crimping the wire 19 using the mandrel 6. The cylinder formed part of the socket 17 is facing the surface 12 of the matrix 11 for the purpose of preventing a thickening of the socket 17 by the crimping.

In FIG. 4 is shown a table of results from practical tests in which all tests has an acceptable connection between socket and wire. In column A is stated the area in mm of the wire. In column B is stated the outer diameter of the socket 17. In column C is stated the pressure force in tons of the first indentation and in column D is stated the pressure force in tons of the second indentation and in column E is stated the average value.

It is to be noted that the socket and the wire has the same material and that the socket has a central recess in the form only little exceeding the wire area.

It is further to be noted that the stated tests have been carried out in such a manner that the indentation 20 has been pressed first and the indentation 20' has been pressed later on. In column C is stated the first indentations and column D is stated the second indentation, which gives an explanation of the higher value in column D.

In FIG. 5 is shown the relation between the pressure force G and the area A.

From the tests is clear, which is seen in FIGS. 4 and 5, that the pressure force is essentially constant for one and the same outer diameter of the socket 17. This is probably depending upon the fact that the material is choosen the same as of the wire 19. Moreover it is clear that an increase of the diameter of the socket 17 causes an increase of the force.

It is especially noted in FIG. 5 that the force G increases when the area increases. This fact states that the force in tons shall exceed the value in the formula when A in the area is mm of the wire.

On the other hand it is clear that the force in tons shall not exceed the value in the formula G=Al38 3.0

Between these limits the force might vary. The formulas are valid for A within 25 500 mm' or above.

The mandrel used by the tests has in one plane a smooth form. For the value 50 95 in column A is used a matrix having an opening 15 essentially 40 mm and the distance between the surfaces 12' is 47 mm. The mandrel has a breadth in the projection according to FIG. 7' by its base of 15 mm and by its upper part 13 mm. In FIG. 6 the mandrel has a thickness of 9 mm at its base. This means that the mandrel 6 shall have a length compared to the length of the matrix shown in FIG. 2b of 60 percent. By the tests two mandrels have been used and a splitting of the procentage must be done.

It is essentially that the indentations from the mandrel 6 shall cause an area reduction, in a plane perpendicular to the central axis of the wire 19, compared to the original area of the socket and the wire within the range 10 25 percent independently of the total area. Moreover it is necessary that the pressure acting on each mandrel shall be within the range 2.5 15 ton, the lower value is valid for smaller area, as an example 25 mm and the higher value is valid for larger area, as an example 500 mm The area reduction might be within the range 10 20 percent and acceptable results has been noted within the range 12 18 percent.

The invention is not restricted to the shown embodiments but may be changed within the scope of the succeeding claims.

I claim:

1. The method of crimping a socket connector to a rod formed of aluminum material in a manner to prevent lengthening of the connector beyond its original length, which comprises:

a. inserting one end of the aluminum rod material into said socket;

b. placing the socket with the inserted rod material into a closely fitting radial and length-confining region to prevent the socket and the rod material from flowing longitudinally and radially outwardly under pressure;

0. pressing at least one indentation into the outer surface of said confined socket; characterized in that the indentation in said socket is made so the reduction in cross-sectional area for the socket and the rod material will be within the range 10 to 25 percent of the total original cross-sectional area; and further characterized in that the pressure acting on the socket is within the range 2.5 to 15 tons, with the lower value usable for a smaller area of the order of 25 mm and with the higher value usable for a larger area, such as 500 mm'.

2. A method according to claim 1, in which the pressure on the indentation area exceeds the value in the formula G =A/52 1.6 and is below the value in the formula G =A/38 3.0 in which G is stated in tons and A in mm and the value A is within the range 25 to 500 mm 3. A method according to claim 2, in which the mateoriginal cross-sectional area. 

1. The method of crimping a socket connector to a rod formed of aluminum material in a manner to prevent lengthening of the connector beyond its original length, which comprises: a. inserting one end of the aluminum rod material into said socket; b. placing the socket with the inserted rod material into a closely fitting radial and length-confining region to prevent the socket and the rod material from flowing longitudinally and radially outwardly under pressure; c. pressing at least one indentation into the outer surface of said confined socket; characterized in that the indentation in said socket is made so the reduction in cross-sectional area for the socket and the rod material will be within the range 10 to 25 percent of the total original cross-sectional area; and further characterized in that the pressure acting on the socket is within the range 2.5 to 15 tons, with the lower value usable for a smaller area of the order of 25 mm2, and with the higher value usable for a larger area, such as 500 mm2.
 2. A method according to claim 1, in which the pressure on the indentation area exceeds the value in the formula G A/52 + 1.6 and is below the value in the formula G A/38 + 3.0 in which G is stated in tons and A in mm2 and the value A is within the range 25 to 500 mm2.
 3. A method according to claim 2, in which the material of the socket and the material of the wire are so chosen that the area reduction is essentially equal in the two parts.
 4. A method according to claim 1, characterized in that the area reduction is within the range 10 to 20 percent of original cross-sectional area.
 5. A method according to claim 4, in which the area reduction is within the range 12 to 18 percent of the original cross-sectional area. 